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UNITED STATES PATENT OFFICE.

CABLE-TON EILES, O1 MONTCLAIR, NEW JERSEY, AND MORTIMER J. COHEN, OF NEWYORK, N. Y., ASSIGNORS, BY ASSIGNMENTS, TO SETH B. HUNT, TRUSTEE,

OF MOUNT KISCO, NEXV YORK.

PROCESS OF DIRECTLY ESTERIEYING OLEFINS AND PRODUCT THEREOF.

No Drawing.

0 all whom it may concern:

Be it known that we, Cameron Ennis and Mon'rmrnn J. COHEN, citizens ofthe United States, and residents of Montclair, county of Essex, andState of New Jersey, and New York, county of New York, and State of NewYork, respectively, have invented certain new and useful Improvements inProcesses of Directly Esterifying Olefins and Products Thereof, of whichthe following is a specification.

Our invention relates to the esterification of olefins and the productsof esterification.

One object of the invention is the provision of a process by means ofwhich an organic acid, such for example, as acetic acid or formic acid,may be combined directly with an olefin or olefins, even in the presenceof saturated hydrocarbon diluents, such, for example, as volatilehydrocarbons of the paraflin series or similar body or bodies.

Another object of the invention is the production of solvent mixtures,suitable for use in pyroxylin and related industries, directly frompetroleum products containing saturated and unsaturated materials by theesterification of the unsaturated olefins without the necessity ofmaking a separation between such materials, although if desired, theesters and the saturated material, as gasolene, may be separatelyrecovered.

While our invention may be applied to olefin materials separate fromsaturated petroleum materials, as gasolene and the like, it ispreferably carried out with a mix ture of saturated and unsaturatedmaterials, such as cracked gasolene, obtained by cracking heavierpetroleum oils in any of the various modes available therefor, or otherpetroleum products containing mixtures of saturated and unsaturatedmaterial, as still gas condensate, and other similar bodies containingsubstantial quantities of the unsaturated olefins.

We have found that when olefins or mixtures of such saturated andunsaturated materials are treated with an organic acid, such as aceticacid, under apparently favorable conditions for reaction, such as theprovision of an excess of the acid, or the application of heat, as bymeans of heating under a reflux condenser over considerable periods,substantially no esterification of the olefins takes place, and that inthe absence of suit- Specification of Letters Patent.

Patented Jan. 11, 1921.

Application filed June 30, 191%. Serial No. 106,769.

able material as hereinafter set forth, in addition to the olefins andthe organic acid or acids, which it is desired to unite, no sub stantialresults can be obtained in the way of combining the organic acid withthe unsaturated material.

lVe have found, however, that when a proper activating third material orsub stance is present, such direct addition of the organic, as acetic,acid or a mixture of organic acids to the olefins may be effectivelycarried out, and we have found that among the activators having thiseffect concentrated sulfuric acid up to, say, about 10% or more of theacetic acid used is effective as an activator in bringing about thedesired reac tion. Other activators may, of course, be used, as, forexample, hydrochloric acid, phosphoric acid and other materials andsubstances which have the effect of bringing about the desired reaction.

The presence of water appears to be unfavorable to such direct additionreaction, and for this reason the organic acid used should be insubstantially anhydrous state, as when acetic acid is used the acidshould be glacial acetic, and for other organic acids the acid should beas nearly as possible in the anhydrous state.

The glacial acetic acid used, when an acetic ester or esters is or areto be made, may be either in substantially pure form, as may be preparedin advance, or a salt of acetic acid may be utilized, as calciumacetate, and this salt reacted upon by an acid as sulfuric acid, forminga pasty mixture of calcium sulfate and the glacial acetic acid.

In working on mixtures of saturated and unsaturated materials, such ascracked gasolene, containing olefins with acetic acid, such petroleummixture and the glacial acetic acid or glacial acid containing materialsuch as prepared from calcium acetate in the manner described aremingled together, as by adding either to the other, the acetic acidbeing preferably in excess of the amount required for acetylation of theolefins of the concentrated sulfuric acid is present to take up anywater which may be present without material dilution of the sulfuricacid to, say, below specific gravity of 1.7 or at least a point not aslow as specific gravity 1.57. The activator may be applied when a saltof the organic acid is utilized, as above, by providing a suitableexcess of sufficiently strong sulfuric acid in making the glacial aceticacid, it being unnecessary in such case to supply the activatingsulfuric acid separately.

These materials may be placed in an apparatus such a digester equippedwith a reflux condenser, and after heating, say, for a period of acouple of hours or so, and under atmospheric pressure or in some casesunder super-atmospheric pressure, the esterfication of the olelins bythe organic acid will have progressed. in large measure or tosubstantial completion.

After the reaction has been completed to a sufficient extent the excessacetic acid and sulfuric acid may removed by washing, and the washwaters may be siphoned or otherwise taken off and the acids suitablyrecovered, if desired, and the salt, as calcium sulfate, if present, maybe separated out as by centrifuging, filtration and the like operations,and the materials remaining, consisting in part or principally of theesters of the various oleiins, which, in the case mentioned, are theacetates, the saturated hydrocarbons originally present with traces offree oleiins remaining and small quantities of polymers of the olefinsand sulfonated tarry bonies formed by the action of the sulfuric acid onthe olefins, be subjected to fractional distillation and separated. If afraction of cracked material is used having a boiling point of, say,below 100 C, the acetates corresponding to the olefins thereof boilapproximate between 100 and 200 (1., generally above 115 C., so that thematerial going over up to, say, 100 C. consists principally ofunsaturated hydrocarbons witn traces of olefins in their unchangedcondition, and at temperatures of 115 and above the acetates may beseparated and at substantially higher points the polymerized bodies,which consist of heavier oils, as kerosene, lubrieating oil and thelilac, leaving the tarry and sulfonated bodies in the condenser andwhich may be discarded or distillation carried on until the residue hasbeen distilled or coked.

Or to obtain the acetates in substantially pure form separation bysulfuric acid of sp. gr. 1.57 may be resorted to in place of sepa rationby fractional distillation, the esters being soluble in sulfuric acid ofthis strength in which the hydrocarbons, includ-' ing such oleiins asmay be present, are in soluble may be separately drawn ofi- By thendiluting the sulfuric acid solution of esters to a point to bring theacid sub stantially below sp. gr. 1.57 the esters are separated fromsolution and form a top layer which may readily be drawn off or beneathwhich the weak acid may be drawn off from below; Then if desired theesters may be further purified by distillation and any traces of estersleft in the weak acid may be similarly recovered as well as any estersleft in the hydrocarbon material. The dilute acid may be concentratedfor reuse.

in the above and other ways substantially pure esters may be obtainedand separately reco ered either singly or as a mixture of esters fromolefins or mixtures from hydrocarbon materials containing olelins ormixtures of olefins. 1

t is not essential, however, that there be such separation from thesaturated gasolene or other saturated material, for in many arts, as inthe dissolving of guncot-zon, it

common to resort to the use of mixed solvents containing a substantialquantity of saturated material such as gasolcne, and for such usessuitable mixed solvents may be prepared directly without the necessityof resorting to separation work such as described.

in the production of such ready mixed solvents the fact that thecracking process may be controlled so to govern the proportion ofolefins produced is of importance. As is well known, cracking undercomparatively low pressures tends to produce cracked ma terial rich inoleiins, while higher pressures tend to produce a relatively largerproportion of saturated material, and there are or conditions subject tocontrol which t the relative proportions of saturated and unsaturatedmaterials yielded and which need not be referred to in detail here,important fact being that it is possible control relative proportions'of saturated and unsaturated materials produced. .ziccordingly, when asolvent containing specified proportions of, say, gasolene and es of theolefins is desired, it is only sary to provide a cracked gasoleneconsubstan ially the desired proportion the y, of course, the necessityof separating out any excess organic acid used, together with theactivating material, as sulfuric acid, and the removal of any salts, ascalcium sulfate, which may be present, or, if desired, the hydrocarbonsand esters may be separately recovered, and when separately andsufficiently freed of undesirable materials may again be commingled toserve their solvent uses, with or Without the addition of othersolvents, as in a case Where a more complex solvent formula is beingfollowed. In this way very substantial economies in the production ofmixed solvents may be effected.

The direct production of esters by the 5 union of an organic acid withthe olefins and the obtaining of results such as outlined above isdependent upon the presence of an activating material in bringing aboutthe reaction. As such activating material in the case of sulfuric acidreferred to is substantially completely recovered, its action may beconsidered at least in a broad sense to be that of a catalyzer, and itis with this property in View of bringing about the de sired reactionwhile still being recovered in substantially its original condition thatthe term catalyzer is made use of in our claims. By such use, however,we are not to be understood as excluding the possibility of intermediatereactions taking place, the ultimate result of which may be, so far asthe activator is concerned, to restore it to its original condition whenthe desired reaction resulting in the addition of the organic acid oracids to the olefin or olefins has been effected. Thus when usingsulfuric acid in this capacity, alkyl sulfuric acid may be formed insome cases as an intermediate product.

We are not to be limited by the following example given as anillustration and for affording a clear understanding of one way in whichthe invention may be carried out. For example, other activators may beused than stated, so long as they have the effect of bringing about thedesired direct reaction, and other organic acids and hydrocarbonmaterials may be used, and when sulfuric acid is used as an activatorsubstantially smaller quantities than stated may be used, so long as theorganic acid is kept substantially anhydrous. We have obtained goodresults with lesser quantities of sulfuric acid than 10%, and, ifdesired, more of the sulfuric acid may be used, it being desirable,however, not to make use of unduly large quantities of such mineral acidbecause of the tendency in such case of the olefins to become sulfonatedand to produce objectionable tarry materials and heavy polymers of theolefins, which are preferably avoided so far as may be.

Following is an example showing one way in which the invention may becarried out:

A mixture was made of about 20 parts of cracked petroleum materialboiling below 100 0., about 100 parts of glacial acetic acid and about10 parts of sulfuric acid of 1.8 specific gravity. The mixture washomogeneous and clear and on heating assumed a dark greenish color. Theentire mass was heated under a reflux condenser for three hours and atthe end of this time was washed with water to remove any excess ofsulfuric 6 acid and glacial acetic acid. The remaining oil, which wasdark red in color, was treated with sodium carbonate solution toneutralize any excess acid retained. This oil had the odor of theacetates and its saponification number was equal to 17 1, whichindicates 7o 45% acetate content referred to hexyl acetate. It isevident then. from the foregoing acetate content that practically 100%conversion was obtained, viz: Substantially all the olefin materialcontained in the origi nal cracked oil amounting to approximately 45%was converted into acetate. This oil dissolved pyroxylin very rapidlyand on distillation the distillate was water-white, the boiling pointsof the product lying mainly between 125460. Ready separation was made bythis simple distillation method, since the original cracked materialboiled mainly below 100 and contained principally simple normal olefins.However, if 5 contaminated by unsaturated hydrocarbons retained, theymay be separated out with sulfuric acid of 1.57 sp. gr., which may beadded to the mixture of acetate and hydrocarbon oil, the former beingdissolved by the sulfuric acid and the latter left untouched andsubsequently separated and the mixture of acetates recovered by simplyadding to water and collecting the liberated acetates.

Where adding one material to another is referred to in our claims, theuse of this term or similar expression includes bringing the materialstogether in any preferred way, or in any order; and by the use of theterm heating in our claims is meant the application of heat sufficientto bring about the desired reaction.

Having thus described our invention, we claim:

1. The process of making ester material which consists in combining byheating a fatty acid with an olefin hydrocarbon in the presence of anacid catalyzer.

2. The process of making ester material which consists in combining, byheating at atmospheric pressure, substantially anhydrous acetic acidwith an olefin hydrocarbon in the presence of a small quantity ofsulfuric acid.

3. The process of making composite ester material which consists incombining, by heating at atmospheric pressure, substantially anhydrousacetic acid with a complex mixture of olefin hydrocarbons in thepresence of sulfuric acid.

t. The process of making solvent material which consists in combining anorganic acid with a complex mixture of olefin hydrocarbons in thepresence of a substantial portion of saturated hydrocarbons by heatingwith a catalyzer.

5. The process of making solvent material which consists in directlyuniting by heating an organic acid with the olefins contained in crackedgasolene in the presence of an acid catalyzer.

6. The process of making solvent material which comprises convertingcracked gasolene containing saturated and unsaturated hydrocarbons intoa mixture consisting substantially of saturated gasolene and acetatescorresponding to unsaturated hydrocarbons by heating with substantiallyanhydrous acetic acid on the unsaturated hydrocarbons in the presence ofa mineral acid catalyzer.

7. The process of making solvent material which comprises directlyconverting cracked gasolene containing saturated and unsaturatedhydrocarbons into a mixture consisting substantially of saturatedgasolene and acetates corresponding to unsaturated hydrocarbons byheating such gasolene with acetic acid at substantially atmosphericpressure in the presence of a catalyzer comprising sulfuric acid.

8. The process of making solvent material which comprises directlyconverting cracked gasolene containing saturated and unsaturatedhydrocarbons into a mixture consisting substantially of saturatedgasolene and acetates of unsaturated hydrocarbons by heating withsubstantially anhydrous acetic acid at atmospheric pressure in thepresence of a small quantity of sulfuric acid not exceeding 10% of theacetic acid used.

9. The process of making solvent material which comprises heating ahydrocar-- bon liquid, containing a substantial proportion of olefinhydrocarbons, with an excess of acetic acid, in presence of sulfuricacid.

10. A mixed solvent comprising saturated hydrocarbons, and a mixture ofthe esters corresponding to the olefins of cracked gasolene.

11. A mixed solvent comprising saturated hydrocarbons, and a mixture ofthe acetates porresponding to the olefins of cracked gasoene.

In testimony that We claimthe'foregoing, we hereto set our hands, this28th 'day of June, 1916.

GARLETON ELLIS. MORTIMER J. COHEN.

